Conventionally is known the structure in which hologram which is difficult to duplicate is affixed as an identification label to objects such as magnetic cards and other information storage cards, stocks and bonds, tickets, and other commercial goods to identify their authenticity, and such a label is disclosed, for instance, in Japanese utility model laid-open publication (kokai) No. 61-182580.
However, such an identification label is necessarily affixed to a location which can be readily and visually identified because it is required to be visually identified. Therefore, the freedom of the design of the object tends to be reduced because the position, shape and color of the identification label must be considered as a part of the design, and the external appearance of the object may be seriously impaired because of the failure to achieve an acceptable design balance.
According to the disclosure of Japanese patent laid-open publication (kokai) No. 3-71383 by the applicant of this patent application, a hologram area having a unique diffraction property is provided on the surface of an object, and this hologram area is identified with an identification unit serving as optical identification means. By using this structure, since the object consists of an object having a fixed shape, such as information storage cards, stocks and bonds, and tickets, and the identification process is carried out by the identification unit, it is possible to place an identification label at an inconspicuous location on the object and to improve the freedom in the design of the object, but the very existence of the identification label on the surface of the object could not totally eliminate the restriction on the design of the object.
Meanwhile, as for the system in which the identification process is carried out with a machine, since the operator is not required to heed the location at which the identification label is placed, it is preferable to make the visual recognition of the existence of the identification label difficult as much as possible to the end of discouraging any attempt to duplicate the identification label with an fraudulent intent.